As expected, in the women's gymnastics preliminaries, the United States topped the field. Less expectedly, the margin was only 1.4 points.

And completely unexpectedly, world champion Jordyn Wieber failed to qualify for the individual all-around final, to compete for the most coveted title in gymnastics.

Wieber didn't have a meltdown or fall off the equipment. She had a very good meet with a few minor errors, breaking 60 points. Her 60.032 was the fourth-highest score in the whole preliminary field, 0.6 points behind the leader, Russia's Victoria Komova.

But the rules stipulate that only two gymnasts per country advance to the all-around final. And two of Wieber's teammates, Aly Raisman and Gabby Douglas, edged her out for second and third.

This means that a whole pack of gymnasts who did worse than Wieber will be competing for the all-around medal, while she sits out. Wieber even outscored the second-ranked Russian, 2010 world champion Aliya Mustafina, who is in fine form after tearing her ACL last year.

Yet while the 28th-ranked gymnast (Australia's Ashleigh Brennan, with a 54.232) gets a shot at all-around title, the fourth-ranked one is out.

The former Soviet Union used to get around this rule by faking an injury to one of the qualified athletes. Back in 1992—when the top three per country advanced to the all-around final—pre-meet favorite Tatiana Gutsu fell off the beam and failed to make the top three on the powerful Unified Team. So the team simply claimed that Roza Galieva had a knee injury and subbed in Gutsu, who ended up winning the whole competition. It was only a few years later that Galieva herself revealed that she in fact had not been injured.

But the American team isn't working up any orthopedic fictions to save Wieber's spot. Though most of the media hype had surrounded Wieber and Gabrielle Douglas, it's Alexandra Raisman who enters the all around final as the top-ranked American gymnast. She, like the rest of the Americans, did great on vault and she more than survived bars, her worst event. After that, it was smooth sailing on beam and floor exercise ahead of Douglas, who had a significant stumble on the floor.

While Wieber's elimination was shocking and weakened the all-around field, Raisman's ascension is not all that surprising to viewers who've been paying attention all season. Though she will never be a strong bar worker, she has steadily improved at it, and she has the highest difficulty scores on beam and floor of the Americans. And she rarely ever misses in competition.

(Kyla Ross, the youngest member of the U.S. team, was fantastic too, despite having very little international experience. If not for the two-per-country rule, she would have made the beam final, and she was close on the bars.)

Raisman placed second overall, right behind a reinvigorated Komova, who competed with new elements on all of the events except floor exercise. With Wieber out, Komova looks like the favorite to win the all-around gold.

The rest of the Russians competed with the same energy and ease that Komova displayed. They also beefed up their vault rotation, which is key if they're to top the U.S. in the team finals. Komova landed a nice Amanar, and Maria Paseka, who was named to the team purely for her ability to do that vault, also stood hers up, albeit very sloppily. While the U.S. remain the favorites, they will have to fight harder than they previously thought for the team title.

There was quite a big dropoff after the top two. The Chinese gymnasts landed in third on the strength of their bars, but the had very weak vault and floor rotations. And Romania, which had competed so assuredly against an injured Russian squad at the European Championships, didn't have a good outing either. Their all-around favorite, Larisa Iordache, fell on floor and had lackluster efforts on the other events, failing to qualify to a single apparatus final. Still, she placed ninth overall, 2.5 points behind Wieber. And none of her teammates beat her out—so, unlike Wieber, Iordache will be going to the all-around final.